Late maturing breeds do better
This option may reduce costs of production by eliminating the final housing period. But as most suckler steers are late-maturing, achieving an adequate carcass fat cover at a younger age may be challenging.
Research was undertaken at Teagasc Grange to determine growth and carcass of early and late-maturing steers slaughtered before the second wintering period.
Spring-born Aberdeen angus and Hereford (early maturing), and charolais and limousin (late maturing) sired weanling steers from the suckler herd were used.
All animals had a winter store period indoors, after which they were either grazed for 175 days, grazed for 100 days followed by 75 days at pasture supplemented with 5kg (fresh weight) of concentrate daily, or grazed 100 days followed by 75 days indoors on ad lib concentrate. Animals were slaughtered after 175 days, at about 19 months old.
The un-supplemented early maturing cattle had carcass weight of 282kg and a fat score of 3- (three minus). The 5kg of concentrate increased the carcass by 27kg (a response of 14kg concentrates for 1kg carcass gain) and fat score to 3= (three equal). Feeding them adlib concentrates indoors for the last 75 days increased carcass weight by 49kg (17:1 response) and fat score to 3+/4- (three plus/four minus).
Late maturing animals reached average carcass weight of 300kg, and fat score of 2= (two equal). The 5kg of concentrate increased the carcass by 38kg (10:1 response) and fat score to 3- (three minus). Adlib concentrates indoors for the last 75 days added 63kg (13:1 response), and took fat score to 3= (three equal).
Overall, early maturing cattle were lighter and fatter and had poorer carcass conformation, and a lower response to concentrates.
Compared at a similar slaughter age, late maturing animals had significantly higher slaughter weight, kill-out proportion, carcass weight, and carcass conformation score, and lower carcass fat score.
And increasing the concentrate levels in the final 75 days significantly increased all of these carcass traits, resulting in a significantly higher average daily live weight gain than the early maturing group.
